• Journal of Korean Society on Water Environment
• /
• v.22 no.5
• /
• pp.871-878
• /
• 2006

Batch experiments were performed to evaluate the applicability of soil washing for heavy metal contaminated soils at Nacdong and Hamchang abandoned mines. The texture of the Nacdong soil was sandy loam. Nacdong abandoned mine soil was almost neutral (pH=6.5). Contaminations of As, Cd, Pb and Zn for Nacdong mine soils were 12,900 mg/kg, 29 mg/kg, 696 mg/kg and 276 mg/kg, respectively. Hamchang abandoned mine soils were acidic (pH=2.6) and the soil texture was loam. The contaminations of As, Cd, Pb and Zn for Hamchang abandoned mine soils were 6,410 mg/kg, 291 mg/kg, 1,300 mg/kg and 1,110 mg/kg, respectively. For the Nacdong abandoned mine soils, oxalic acid was found to be the most effective soil washing extracter for As and Pb while citric acid was the most effective extracter for Cd. For the Hamchang abandoned mine soils, oxalic acid showed the highest extraction efficiencies for As and Pb, whilst citric acid presented the best soil washing efficiencie for Cd. Oxalic acid and EDTA were found to be the most effective soil washing extracter for the Hamchang abandoned mine contaminated soils.

• Applied Biological Chemistry
• /
• v.25 no.3
• /
• pp.126-134
• /
• 1982

When $^{14}C-2$, 6-Diethylaniline (2, 6-DEA) was incubated aerobically in soil, $^{14}CO_2$ evolved from non-sterile soil A and B was 6.5 and 10.1%, respectively, in the 21st week. Methanol could extract 3.1 and 13.5% of the radioactivity from soil A and B, respectively, 2, 6-Diethylacetanilide was detected as a degradation product in soil. Chaetomium globosum produced 2, 6-diethyl-p-benzoquinone as a degradation product in pure culture. A possible pathway was proposed to include p-hydroxylation of 2, 6-DEA, formation of quinoneimine, and the subsequent hydrolysis with the release of ammonia.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.5 no.4
• /
• pp.7-12
• /
• 2006

Galvanized steel pipe, copper pipe and stainless steel pipe, which is being used in waterworks piping materials. In case of galvanized steel pipe, the precipitation of a product is being generated due to the pollution of the tap water, a white water phenomenon, and various corrosion reaction because a zinc ion is melted by tap water. And in case of a cupper pipe, many problems which is harm in sanitation appeared because of a inflow of harmfulness substance by a frequent accident of a water leakage. So, to prevent these problems, it is substituted for stainless steel pipe. However, those problems is still occurring because of badness of welding, a problem of a water leakage in connection part, and a increment of construction expenses. Therefore, this research has examined the laying period according to each piping thickness and a corrosion shape according to each laying depth after laying in various soils(sandy loam, loamy, clay loam, clay) using galvanized steel pipe, copper pipe, and stainless steel pipe. That is, we has studied the data which is necessary for a rational method of preserving the quality of water by examining the corrosion properties of piping materials in the soil environment which waterworks piping materials is being used.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.4
• /
• pp.545-550
• /
• 2011

Urea intercalated into montmorillonite (MT) exhibits remarkably enhanced N use efficiency, maintaining its fast effectiveness. This study dealt with the release property of urea from metal-urea-clay hybrid with MT (MUCH) under continuous-flow conditions and the cumulative impacts of its successive application on physicochemical properties of soils. Releases of urea were completed within 4 hrs under continuous-flow condition regardless of the types and the leaching solutions. However, urea release property was significantly affected by both the form of fertilizer and the presence of electrolytes in solution. The fast release property of urea from MUCH in continuous-flow condition was not significantly affected by soil properties such as soil pH and soil texture. In addition, its successive application did not lead to any noticeable change in soil physicochemical properties, water stable aggregate rate, water holding capacity and cation exchange capacity in both sandy loam and clay loam soils. Therefore, this study strongly supported that urea intercalated into MT could be applied as fast-effective N fertilizer, in particular for additional N supply.

• Journal of Forest and Environmental Science
• /
• v.37 no.1
• /
• pp.25-34
• /
• 2021

This study was conducted at Sitakunda coastal afforestation range, comprised of four beats- Bansbaria, Bakkhali, Baterkhil and Bogachattar, in Chittagong. Afforestation effects on soil physicochemical properties in comparison to adjacent barren land were analysed. In the study area, an area of 3277.33 ha was planted with Sonneratia apetala, Avecinnia officinalis, Excoecaria agallocha, Bruguiera sexangula, Ceriops decandra from 1968 to 2011. We found positive soil physicochemical changes in plantations in comparison to adjacent barren land. Soil bulk density of plantation was lower than the adjacent barren land. Soil pH and soil salinity were significantly higher in barren land whereas soil organic matter, organic carbon, nitrogen, phosphorus, potassium of plantations were higher in afforested land. Soil texture ranged from clay loam to sandy loam in different depth of these two types of land. However, this study concludes that there is clear evidence that afforestation has positive impacts on all soil properties in different location and soil depths in the study area.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.353-359
• /
• 2012

The identification of effective root zone would clarify dynamics of plant available water and soil water balance. Using the relationship between soil properties and electrical resistivity (ER) the purpose of this research is to identify soil zone affected by a plant root activity using electrical resistivity tomography (ERT) technique. Four plastic containers were prepared for two different soil textures (clay and sandy loam) and one container for each texture was selected for planting four corn seedlings (Zea mays L.) and the others were prepared for the blank. For ERT monitoring, we prepared 0.8 m plastic sticks with 17 electrodes installed with 5 cm space. The Ministing (AGI Inc., Texas) instrument for electrical resistivity measurement and semi-auto converter of electrode arrangement were set up for dipole-dipole array. During 2 months of the corns growing, ERT monitoring was made 3 to 4 days after the irrigation practice. Despite of the same amount water supplied into soils, two textures showed very different apparent resistivity values due to different clay content. The apparent electrical resistivity is consistently lower in clay loam comparing to sandy loam soil implying that plant root does not significantly alter the overall trend of resistivity. When plant root system, however, is active both soils with plants showed 2-7 times higher electrical resistivity and higher coefficient variation than soils without plant, implying the effect of root system on the resistivity, in which may caused by. This result suggests plant root activities regulating the soil water dynamics mainly control the variation of electrical resistivity over soil textural difference. Therefore the identification of water uptake zone would highly be correlated to plant root activities, thus ERT will be feasible approach to identify spatial characteristics of a plant root activity.

• Journal of Environmental Impact Assessment
• /
• v.25 no.6
• /
• pp.369-383
• /
• 2016

A distributed watershed model CAMEL(Chemicals, Agricultural Management and Erosion Losses) was applied to a part of grazing grassland and vegetation buffer strip(VBS) located in Daegwanryeong, Korea. A set of scenario analyses was carried out for grassland and VBS with various combinations of VBS widths, soil textures and ground surface slopes. The simulation results indicate that annual direct runoff decreases with wider VBS and the removal efficiency of pollutants generally decrease with steeper slopes. The removal efficiency of sediment is not significantly different with VBS widths. For gentle and medium slopes($10^{\circ}$, $20^{\circ}$), the removal efficiency of TOC and TN is not significantly different with VBS widths. As for a steep slope($30^{\circ}$), however, the removal efficiency of TOC and TN increases with narrower VBS. The removal efficiency of TP is generally high except for medium and steep slope of sandy loam where the removal efficiency of TP increases with wider VBS. This result of TP is contrary to the results of TOC and TN due to the adsorption characteristics of phosphorus associated with fine sediment particles. It is expected that CAMEL can be used for evaluating the effectiveness of VBS to reduce non-point source pollution discharges.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.2
• /
• pp.105-118
• /
• 2015

This study was carried out to investigate the effects of profile disturbance with different artificial accumulation history on physico-chemical properties of soil under plastic film house. The investigations included soil profile description using soil column cylinder auger F10cm x h110cm, in situ and laboratory measurements of soil properties at five sites each at the cucumber (Site Ic ~ Vc) and grape (Site Ig ~ Vg) plastic film houses with artificial soil accumulation. The sites except sites Ic, IVc, IVg and Vg, belong to ex-paddy area. The types of accumulates around root zone included sandy loam soil for 3 sites, loam soil for 1 site, saprolite for 2 sites, and multi-layer with different accumulates for 3 sites. Especially, Site IIg has mixed plow zone (Ap horizon) with original soil and saprolite, whereas disturbed soil layers of the other sites are composed of only external accumulates. The soil depth disturbed by artificial accumulation ranged from 20 cm, for Site IIg, to whole measured depth of 110 cm, for Site IVc, Vc, and Site IVg. Elapsed time from artificially accumulation to investigation time ranged from 3 months, Site IIc, to more than 20 years, Site Vg, paddy-soil covering over well-drained upland soil during land leveling in 1980s. Disturbed top layer in all sites except Site Vg had no structure, indicating low structural stability. In situ infiltration rate had no correlation with texture or organic matter content, but highest value with highest variability in Site IIIc, the shortest elapsed time since sandy loam soil accumulation. Relatively low infiltration rate was observed in sites accumulated by saprolite with coarse texture, presumably because its low structural stability in the way of weathering process could result in relatively high compaction in agro-machine work or irrigation. In all cucumber sites, there were water-transport limited zone with very low permeable or impermeability within 50 cm under soil surface, but Site IIg, IIIg, and Vg, with relatively weak disturbance or structured soil, were the reverse. We observed the big change in texture and re-increase of organic matter content, available phosphate, and exchangeable cations between disturbed layer and original soil layer. This study, therefore, suggest that the accumulation of coarse material such as saprolite for cultivating cash crop under plastic film house might not improve soil drainage and structural stability, inversely showing weaker disturbance of original soil profile with higher drainage.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.3
• /
• pp.262-270
• /
• 2012

This research was performed to find out the root characteristics of sweetpotato (Ipomoea batatas LAM.) cultivars according to the cultivation regions. Total 10 sweetpotato culivars, 6 yellow, 2 purple and 2 orange, were used for experiment. Samples were cultivated in Muan, Iksan, Nonsan, Boryeong and Hamyang. Precipitation and average temperature during the growth period of sweetpotato cultivation were 882~1,682 mm and 16.7~$28.2^{\circ}C$, respectively. Accumulated temperature was 3,122~$3,282^{\circ}C$. Soil texture was found of sandy loam in Muan, Iksan and Boryeong, sandy clay loam in Nonsan, and loam in Hamyang. The yield of root, dry matter content, starch value and soluble solids contents were high in Muan. The length/width ratio was high in Hamyang. The color values of sweetpotatoes were high in Nonsan. The protein content of sweetpotato powder was high in the Iksan, crude fat content and ash content were high in the Hamyang. The results of this study, we could see that root characteristics of sweetpotato in the same cultivars appeared differently depending on the cultivated regions.

• Korean journal of applied entomology
• /
• v.33 no.3
• /
• pp.159-162
• /
• 1994

An ecological skdy of the root-knot nematode, Meioidogyne hapio on medicinal herbs in Eui-sung area was pelformed seasonal occurrence of M hapla on Paeonia iactffiora showed four peaks In a year at the field: early Apnl. mid June, late July, late August. Soil characteristics affected nematode d~shibution and poplation Juvenlle population of the nematode was the highest in sandy and sandy loam sail. The number of the nematode lawae was 10G4-1486 per 300mi of sod wllhin 15cm from the sulfate at P. ioctitiora held. The ncrnatode was distributed even under 50cm.